Kane
by pendragon-companion-at-221b
Summary: AU in which the BBC Sherlock characters are students at Hogwarts - but there's a new mystery in the castle. What's going on with Sherlock and John's Potions professor?
1. Chapter 1

**Chapter 1**

Sherlock Holmes tightened his new blue and gold silk tie in his obsessively polished mirror. Under his breath, he muttered, "These goddamn uniforms…." He slipped on his robe over it, and snuck off to his normal corridor of Hogwarts Castle to go meet John Watson, his only friend.

John was a sixth year, just like Sherlock. He always wore his gold and crimson ties flat and crisp, and he had special grey wool sweaters he wore under his robe. His friendship with Sherlock was definitely frowned upon, with them being of different houses. However, he had been friends with Sherlock since they were first years and they bumped into each other on the train on the way there.

They were silently walking, robes flowing, as they met in the dark corner that they always did. They stepped out on the balcony, and immediately Sherlock's mind was speeding faster than anyone could ever fathom.

"John."

"What have I done this time, Sherlock?"

"You're walking different, putting more weight on your left foot than your right. Your tie has been ironed thrice now; normally you only do it twice. There's no tea mark on your hand, but instead there's smeared ink. You're nervous, and-"

"Fine, fine, just stop. I have a test in Potions tomorrow," he replied shakily.

"You're lying."

"No, I'm not, Sherlock."

"Yes you are, you can hear it in your voice, and you can see it in your body. You're rubbing the back of your neck, you haven't made eye contact with me all day, and your voice is as weak-"

"Sherlock."

"John, stop interrupting me."

"Sherlock, stop being a know-it-all."

They both paused their banter to let out a chuckle. They had gotten used to the type of conversations they had so often in their precious hidden corner of Hogwarts.

"Anything new in the Slytherin common rooms? I heard one of them gave you the password," John asked timidly. Even though Sherlock was a Ravenclaw by the Sorting Hat, he bided his time observing the Slytherins. Their prefect, Jimmy Moriarty, despised Sherlock, while the rest of the cunning students of green and silver had slowly grown over the years to be fond of him and his quiet, yet judgmental personality.

"Jim - God, he's an idiot - is supposed to change it tomorrow again. I'll figure it out though; I'll be you 10 Galleons it won't take me fifteen minutes."

"You know I don't have 10 Galleons to bet on something I already know you'll do regardless. I may not be as smart as you, Sherlock, but I'm not stupid." John's voice became firm for the first time since they arrived at their balcony. Sherlock silently noted this, as he did every other detail he noticed, be it minute or obvious. Granted, everything was obvious to him, seeing as he had spent free time training his senses to notice what others couldn't.

They heard feet shuffling in the corridor and immediately snapped around to see who was approaching, Sherlock hiding behind John.

The taller Sherlock whispered, "It's just Molly," as she walked carefully around the corner.

John shook Sherlock off his shoulders, to which Sherlock gave a scowl behind his back. "Hi, Molly," John said enthusiastically. "You look nice today."

In reality, Molly Hooper, compared to her normal self, looked horrible today. Her hair was pulled back into a messy ponytail, with other light brown strands falling all over the place, covering her face. Her left cheek was smudged with ink, her house tie was sloppily knotted, and her shirt was halfway untucked and wrinkled severely. Typically, her clothes and demeanor were crisp and the exact same every day. Sherlock took note.

"Um, thanks, John," she said, trailing off.

"Molly, did anything happen today?" Sherlock inquired, with genuine concern and care. His head tilted in a way that it only did for John and Molly, and his tone was softer and fatherly. He held his entire body differently, almost seeming to lean in towards Molly in a show of almost affection.

But Sherlock, in his own mind, could never show affection.

Before Molly could craft a sentence to respond with, Sherlock answered his own question. "Someone, someone you care about, got into trouble today...from your facial expressions it's probably something Professor Kane did in your Potions class," he continued, with his mind racing faster than his mouth could move. "Was it Jalen? Charlie Jalen? Had to be. He's the only other Hufflepuff in your class. Kane is shady, but he's not idiotic enough to do something in front of everyone, so it was something in private. I haven't seen Jalen all day; therefore he must be in the infirmary."

Molly cut him off, obviously in great emotional distress. "Sherlock, stop. I visited Charlie earlier. He said Kane gave him a poisonous potion because he accidentally made an explosion go off in class. It wasn't on purpose, I was there. Plus, Charlie would never do something like that on purpose. He'd never hurt anyone."

"Kane is sketchy. I think there's something going on with him," John speculated. "Maybe he's a Death Eater or something."

"He has a soft spot for animals, though, which is odd. He hates the majority of us but he just loves other life, including Muggle things," said Sherlock, letting out another scowl. He was getting back into his element now, his eyes sparking fiercely with excitement. It was another mystery ripe for him to solve with his best and sole friend.

"But from what Molly said, Kane is completely overreacting. It was just an accident, so what's the issue that requires the poor bloke to be put in the infirmary?" John responded, confused. In comparison to the exceptional mental capacity to Sherlock, John was far behind. However, he was still regarded as intelligent, almost gifted, and received good marks, but Sherlock would never admit that. He was far too prideful to ever let that happen.

Sherlock cracked his signature grin and clapped his hands in excitement. "And that, John, is what we're going to find out."

"Okay, boys," Molly said quietly, "I think I'm going to go and try to sleep now. I might get some food too. Do you want any?"

The young detective and his friends exchanged glances. Sherlock winked, and the two simultaneously shook their heads with mischievous expressions. Molly shook her head, chuckled, and walked down the same corridor she came from.

Once she was out of earshot, John whispered, "You aren't really going to try and do this _again_, are you?"

"What, go against the rules, sneak through the castle, and get a professor in loads of trouble? I wouldn't miss it for the world."

John sighed and followed the departing Sherlock down the hallway, following just a few feet behind him.


	2. Chapter 2

**Chapter 2**

It was 2:37 in the morning precisely when John's peaceful slumber was interrupted by the quiet rapping of Sherlock on his door.

After rolling his eyes and cursing at Sherlock a few times under his breath, he slipped his black wool robe on over his burgundy pants and plain white t-shirt. His ash wand lay on the bedside table, but the half-asleep John left it there out of spite for Sherlock.

The knocking continued, but John opened the door and snapped, "Sherlock, I was asleep!"

"Don't you want to find out what's going on, John?" he replied in a hushed whisper. "Right now is the best time to start finding out." Sherlock had already prepared himself for the rest of the day, with a new set of robes and clean shirt, pants, and a warm, freshly pressed Ravenclaw tie. His wild hair from just a few hours before had turned back into the bouncy black curls that appeared every morning and seemed to disappear after dinner. Sherlock's left hand was suspiciously wrapped behind his back, but John was too incoherent to recognize. The young man secretly wished he had been able to sleep as John could, nightly and without interruption, but deep inside him he had another longing for adventure and a mental challenge.

"Whatever, Sherlock," John retorted drowsily.

Suddenly, out from behind Sherlock's back came a cup of cold water, which was thrown right into John's face.

"What on earth was that for?" he shouted within his whisper, now fully awake and quite irate at the grinning boy standing before him. He angrily rubbed over his face with his hands, and then shook them off, directing the water at Sherlock.

"John, you are such an _idiot_," he said rather loudly with the same familiar grin upon his face.

"When am I ever not for you, Sherlock? Why do you keep me around if I'm such an idiot? I'm always the bumbling idiot, obviously not able to think or act for himself, am I not?"

Sherlock was taken aback by John's sudden outburst, his body recoiling backwards as if he had been physically punched in the face. "I'm sorry," he replied, ashamed and feeling guilty, "I'm sorry I woke you up. Please forgive me. I'll leave now."

Just as he turned to walk away, John laid a caring hand on his shoulder and gave the young Holmes a half-smile. Sherlock shook his hand away and walked down the corridor, his head hung and eyes focused on the gray stone floor.

"_Why do I always have to do that?" _Sherlock thought to himself. "_Why must I always ruin friendships like this? Why can't I have any sense of respect for them?" _He felt extremely sorrowful for what he had said, and he looked back on all of the other occasions where he had insulted John. He was genuinely surprised that he hadn't snapped back at him before, and a lone tear rolled down his cheek.

"_Why do I even exist?" _he finally concluded as he flopped down onto his sloppy, unmade bed. Soon, he drifted to sleep, but his face was filled with pain, grief, and shame.


End file.
